In the present work, hybrid nanocomposites of Zn-Cr layered double hydroxide (ZnCr-LDH) and graphene were assembled successfully via a simple one-step coprecipitation method. The assembly process included the nucleation and growth of ZnCr-LDH crystals and the simultaneous reduction of GO in the absence of additional reducing agents. The experimental results revealed that ZnCr-LDH nanoplatelets with the diameter size of similar to 6 nm were well dispersed on the graphene surface, and as-assembled hybrid ZnCr-LDH/graphene nanocomposites exhibited significantly improved visible-light-driven photocatalytic activity in the degradation of Rhodamine B, in comparison with pure ZnCr-LDH, which was attributable to the unique heteronanostructure of ZnCr-LDH/graphene, facilitating the efficient transportation and separation of photogenerated charges and thus continuously generating reactive oxygen species. The present work could open a new doorway for fabricating visible-light-deriven graphene-based photocatalysts for pollutant degradation via an advanced oxidation process.